Oxy-hydrogen flash detonator tester



A." in. 2'

1936 F. w. HAYWARD ET AL 2,730,893

OXY-HYDROGEN FLASH DETONA'IOR TESTER Filed June 27, 1952 I sSheets-Sheet 1 ATTORNEYS Jan. 17, 1956 F. w. HAYWARD ET AL Filed June27, 1952 FIG.3.

OXY-HYDROGEN FLASH DETONATOR TESTER FIG.5.

3 Sheets-Sheet 2 34 FIGc60 37 I 35 F. W. C. J. K. R.

INVENTORS HAYWARD ZABLOCKI SCRIIBNER ATTORNEYS Jan. 17, 1956 F. w.HAYWARD ET AL 2,730,393

OXY-HYDROGEN FLASH DETONATOR TESTER I5 Sheets-Sheet 3 EXHAUST H2 TANKFiled June 27, 1952 FIG.7.

68 LQ l9 VACUUM PUMP EXHAUST A G F INVENTORS F. w. HAYWARD c. .1.ZABLOGKI K. R. SCRIBNER Q MGEQM RMAA MM,

ATTORNEYS United States .5

plate of the explosion chamber.

OXY-HYDROGEN FLASH DETONATOR TESTER Frank W. Hayward, Port Washington,N. Y., Charles J. Zablocki, Silver Spring, Md and Kenneth R. Scribner,Rochester, N. Y., assignors, by direct and mesne assignments, to theUnited States of America as represented bythe Secretary of the NavyApplication June 27, 1952, Serial No. 296,028

11 Claims. (CI. 73-85) This invention relates to a testing apparatus fordetonators of the flash type and more particularly to an oxyhydrogenflash detonator tester.

Formerly in providing a quality control means for flash detonators theignition point was determined by passing an oxy-hydrogen torch past theexplosive. This method proved unsatisfactory in that the resultsobtained therefrom were completely unreliable. The temperature and flowrates of the gases could not be properly maintained and the torch tipswere damaged from the detonation of the test charge. The inventiondisclosed herein overcomes these objectionable features.

The present invention contemplates the provision of an apparatus adaptedto establish an effective means for testing flash type detonators anddetermining ignition temperatures of the explosive mixtures containedtherein by firingthe detonator within a water cooled explosion chamber.The lower end of this chamber has an opening therein whereby a detonatorholder assembly may be inserted with a detonator to be tested heldtherein and exposed to the hollow interior of the explosion chamber. Onthe upper end of the chamber is mounted a spark plug and master valveassembly. The valve assembly provides a means whereby the oxygenhydrogen gas mixture may be admitted to the interior of the chamber. Inaddition in conjunction with the master valve is provided a means toexhaust the chamber and further to supply compressed air to blow outvapor and foreign particles deposited within the chamber as the resultof an explosion. The chamber is supported upon brackets which areprovided 'with slots within which is slidably and rotatably mounted thedetonator holder assembly. This assembly comprises a triangular blockhaving a bore in each face thereof, each of which bores is adapted toreceive a sleeve which supports the detonator to be tested. A plunger isslidably supported within each sleeve and through ccaction with a camserves to eject the detonator following an explosion. A handwheel isprovided on the outer face of a bracket which is adapted to rotate theentire detonator holder assembly and a latching arrangement coacts withthis handwheel to prevent rotation in a counterclockwise direction. Theholder assembly is supported on arms which are pivoted at their lowerends to a block which is fixedly mounted on a shaft rotatably mounted inthe supporting brackets. Onthe outer end of this shaft is fixed a leverwhich when moved to a horizontal position will lower the entiredetonator assembly out of contact with the lower From the constructionof'the detonator holder assembly it is apparent that, as one sleeve isrotated by means of the handwheel out of alignment with the opening inthe lower end of the explosion chamber, another sleeve moves into thisposition.

As the assembly is rotated the plunger coacting with the cam causes thedetonator in the sleeve being rotated out of alignment with theexplosion chamber to be ejected. It is apparent therefore that there hasbeen provided a detonator tester which overcomes the objections inherentin the prior art structures and which provides a safe efatent O2,730,893 Patented Jan. 17, 1956 ficient means for determining theignition point of detonators.

An object of this invention is the provision of an apparatus for testingflash type detonators for establishing a quality control in which thevariable factors such as the temperature and pressure of the gases maybe accurately controlled.

Another object of the invention presently disclosed is the provision ofa testing apparatus for flash detonators in which the method ofinitiation of explosion by combined shock and heat aflfords a closeapproximation of what occurs in a fuze train where initiation isaccomplished by spit of a primer.

A still further object of this invention is the provision of a flashdetonator testing apparatus which incorporates an ejecting means for afired detonator with a loading means whereby the apparatus may bequickly and safely prepared for a test of a detonator therebyeliminating many of the hazards encountered in prior art structures.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. l is an elevational view of the apparatus embodying the invention;

Fig. 2 is a side elevational view of Fig. 1;

Fig. 3 is a vertical sectional view along the line 3-3 of Fig. 2;

Fig. 4 is an enlarged sectional view of the detonator holder assemblyalong the line 4-4 of Fig. 1;

Fig. 5 is a fragmentary view in elevation of the latching means for thedetonator holder assembly;

Fig. 6 is a fragmentary elevational view at right angles to Fig. 1; and

Fig. 7 is a diagrammatic view of the plumbing em ployed in conjunctionwith the presently disclosed apparatus.

Referring now to the drawings wherein like numerals indicate like partsthroughout the several views there is shown in Fig. 1 the apparatuswhich is supported on base plate 1. Suitably secured to the base plateas by bolts 2 is a pair of brackets 3 the upper ends of which supportthe explosion chamber 4. The explosion chamber comprises a lower plate 5which is secured to the upper ends of the brackets by means of bolts 6.This lower plate supports a cylinder or sleeve 7 upon which, in turn, ismounted the upper plate 8. The upper and lower plates are securedtogether by means of elongated bolts or rods 9 extending therebetweenwhereby the cylinder is tightly held in position. The outer surface ofthe cylinder is suitably grooved to receive cooling coil 11 which isconnected to a water supply. Securely mounted on the upper plate 8 is amaster valve assembly 12 to be later described in detail.

There is provided a pair of bushings 13 mounted on brackets 3 near thelower ends thereof. A shaft 15 extends between these bushings andfixedly mounted on the outer end of the shaft is an arm 16. Suitablysecured on shaft 15 is a block 14 which is provided with an offsetportion 17 upon which upwardly extending arms 18 are pivotally mounted.The upper ends of these arms support the detonator holder assembly 19.Brackets 3 are slotted as at 21 (Fig. 3), to receive portions of theholder assembly. It is apparent that, as lever 16 is rotated from thevertical position shown in Fig. 1 to a horizontal position, the motionof the offset portion 17' of the block will cause the arms 18 to belowered thereby causing the detonator holder assembly 19 to ridedownwardly in slots 21 whereby the holder is moved to a position out ofcontact with the lower plate 5 of the explosion chamber.

The construction of the detonator holder assembly 19 will now bedescribed in detail. Referring to Fig. 4 it will be seen that there isprovided a triangular block 22 having a sleeve 23 secured within a bore24 in each face thereof. Slidably disposed on the outer surface of thesleeve is a flanged cup 25. A compression spring 27 se cured toa flangeon the cup and block 22 serves to urge the cup outwardly. It can be seenthat the lower plate of the explosion chamber is provided with a centralbore 28 within which fits the outer end of the sleeve. Sleeve 23 isprovided with a peripheral recess within which fits an O-ring seal 29 toinsure a leak proof fitting between the sleeve and the plate. Sleeve 23is further recessed as at 31 to receive a detonator holder 32. It isapparent that, when sleeve 23 is 'in the vertical position the detonatorholder is exposed to the hollow interior of the explosion chamber andthebore in the lower plate is effectively sealed.

Triangular block 22 is provided with a bore 33 therethrough and a shaft34 extends from one end thereof through the slot 21 in bracket 3. Uponthis shaft is mounted a handwheel 35. Within bore 33 is a cylindricalblock 36 having a cam surface 37 (Figs. 3 and 4), and having the outerend thereof provided with flat faces 38 (Fi g. 6), which ride withinslot 21 in bracket 3. It will be seen, therefore, that as handwheel isrotated to rotate detonator holder assembly19, cylindrical block 36 willremain stationary. Mounted within sleeve 23 is a plunger 39 whichextends upwardly to a position beneath the detonator holder 32. Acompression spring 40 acting between flanged surfaces on the sleeve andplunger urges the plunger downward into contact with cam surface 37.

From Fig. 4 it can be seen that as handwheel 35 is rotated afterlowering the detonator holder assembly, plunger 39 will be forcedoutwardly by the cam surface thereby ejecting the detonator holder. Atthe same time the sleeve a is brought to the operating position beneaththe cylinder while sleeve b is in a loading position. From thisconstruction it is apparent that a series of tests of flash detonatorsmay be made rapidly and without danger to the operator.

There is further provided a latching means to prevent rotation of thehandwheel 35 in a counterclockwise direction which means is disclosed indetail in Fig. 5. Handwheel 35 is provided with a series of slots 41(Fig. 3), extending therethrough which are spaced 60 apart. Fixedlymounted on a bracket 3 above slot 21 is an arm 42 which extends into aslot 41 when the detonator holder is in the position shown in Fig. 5.Pivotally mounted on a plate 43 secured to bracket 3 below slot 21 is anL-shaped link 44 whose pivot point is shown at 45. Limit stop 46 isprovided to permit rotation of link 44 only in a counterclockwisedirection. Tension spring 47 serves to urge link 44 to the normalposition shown in Fig. 5 with the link in contact with the limit stop.When the detonator holder assembly 19 is lowered by means of lever 16,the end portion of link 44 extends into slot 41 sufficiently to preventrotation of the handwheel in a counterclockwise direction but permittingrotation in a clockwise movement since the link 44 will be cammedoutwardly of the slot 41..

The master valve assembly is shown in section in Fig. 3. In top plate 3of the explosion chamber there is provided a port 48 through which theexplosive gas mixture is introduced. The valve assembly consists of abottom plate 49 centrally bored as at 51 and threaded as at 52 toreceive the lower cylinder head 53. This cylinder head is 7 held inplace on cylinder 54 by means of spring ring 55 and is provided with acentral bore 56. Upper cylinder head 57 is held in place on cylinder 54by means of spring ring 58 and is centrally bored as at 59. Extendingthrough the central bores 56 and 59 in the lower and upper cylinderheads respectively is a piston rod 61 which is slidably mounted thereinand is provided with a piston 62 maintained thereon by means of a springring 63. Piston rod 61 extends through the upper cylinder head and theouter end thereof is provided with a collar 64. Compression spring 65acts between this collar and the upper cylinder head to urge the pistonrod to the uppermost limit of movement thereof. Sealing means of theO-ring type 66 a further provided with a spark plug 71 which serves as ameans forigniting the gas mixture and is provided with a firing circuitof any common variety (not shown). InFig. 2 is also shown a cross bar 72which is mounted between brackets 3 and serves as a stop to limitmovement of block 14 to an aligned position with the lower plate of theexplosion chamber.

In Fig. 7 isshown diagrammatically the plumbing arrangement used inconjunction with the present invention. All valves, other than thoseleading to the gas supply tanks, are of the solenoid type well known inthe art and are normally closed so that energizing the solenoid opensthe valve. Port 67, Fig. 3, is connected to the pipe leading to theinput master valve cylinder whereas port 68 constitutes an air escape.Port 69 in the bottom plate is connected to the tubing leading throughthe manifold to the gas supply tanks and exhaust pump.

in the operation of the apparatus lever 16 is first brought to ahorizontal position whereby the detonator holder assembly is lowered toa position out of contact withthe explosion chamber 4 and that sleeve 23which is in the loading position is loaded with the detonator to betested. Handwheel 35 is then rotated in a clockwise direction wherebythe loaded sleeve is moved to a vertical position in alignment with bore28 in the lower plate of the explosion chamber. The lever 16 is thenmoved to a vertical position whereby the detonator holder assembly movesupwardly and the loaded sleeve is positioned within the bore in thelower plate of the explosion chamber.

The piston 62 and rod 61 are in the upper positiondue to the tension ofspring 65 in which position port 69 is opened. The vacuum pump V is thenenergized so as to evacuate the manifold and firing chamber to a valueas indicated by the pressure gauge P. The explosive gas mixture ofhydrogen and oxygen in the ratio of 2 to 1 is then admitted to thefiring chamber 4 by opening the manual valves C and D. When the desiredquantity of each gas has been admitted into chamber 4, as indicated bythe pressure gauge P, the manual valves C and-D are closed and the inputvalve E to the master valve assembly 12 is opened whereby air underpressure is admitted through port 67 to force piston 62 and rod 61downwardly thereby closing port 69 and locking the hydrogen-oxygenmixture in chamber 4. Valve A is then opened to bleed oif the residualexplosive gas mixture from the manifold leading from valves C and D toport 69. The firing switch. (not shown) is then closed whereby the sparkplug 71 is energized to fire the gas mixture contained in chamber 4. Itis, of course, understood that the ignition of .a predetermined quantityof the hydrogen and oxygen mixture, as indicated by the pressure shownat gauge P, produces a predetermined temperature in chamber 4 and towhich the detonator is subjected, thus firing the explosive mixturecontained in the detonator if the mixture is firable at suchtemperature, or the detonator mixture is not fired if the mixture is notfirable at such temperature. It is clear from the foregoing that aplurality of detonators may be tested for flash firing at selectedtemperatures to determine the mean firing temperature and the high andlow extremes of temperature at which the detonators will fire, andwhether the detonators are within specified limits. Exhaust valve A isagain closed which seals the manifold. The exhaust valve F to the mastervalve assembly 12 is opened whereby the piston 62 and piston rod 61 moveupwardly to the normal position thereby opening port 69. whereupon valveG is opened to connect pressure gauge P to the firing chamber 4 and ifthe pressure read on the pressure gauge P is greater than the knownpressure generated by ignition of the gas mixture, the detonatonhasfired. The detonator holder assembly 19 is then moved downwardly out ofthe firing chamber 4 and valve B is opened whereby the firing chamber iscleared of any debris by an air blast. The apparatus is then preparedfor another test by repeating the above cycle of operations.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent is:

l. A flash fired detonator testing apparatus comprising, an explosionchamber having an opening therein, holding means for containing saiddetonator and adapted to be moved into engagement with said chamber toclose the opening therein, means for admitting an explosive gas mixturehaving a predetermined flash temperature to the interior of saidchamber, and means for providing a spark Within said explosion chamberto subject the detonator under test to said predetermined flashtemperature of said explosive gas mixture thereby firing a satisfactorydetonator.

2. In a device of the class described, a hollow housing having anopening therein, movable means for supporting a flash fired detonatorwithin said opening so as to be exposed to the hollow interior of saidhousing, means in cluding a valve assembly for admitting to the interiorof said housing at predetermined pressures, predetermined quantities ofan explosive gas and a combustion supporting gas having combustiontemperature characteristics corresponding to a desired flash pointtemperature for firing a detonator under tests as an explosive gasmixture having a predetermined flash temperature and spark producingmeans mounted on said housing for igniting said explosive gas mixturethereby to fire an acceptable detonator.

3. In a testing apparatus for flash detonators, a firing chamberprovided With a bore in the lower end thereof, vertically movable meansfor holding a detonator to be tested mounted beneath said firing chamberand adapted to be moved into a position wherein said means closes theopening in said firing chamber with the detonator held therein exposedto the hollow interior of said chamber, means including a valve mountedon said chamber adapted to admit an explosive mixture of predeterminedquantities of a flammable gas and a combustion supporting gas thereto ata predetermined pressure, and spark means mounted on said chamberadapted to ignite the explosive gas mixture thereby to fire anacceptable test detonator.

4. A detonator testing apparatus comprising, means providing a firingchamber having an opening in the lower end thereof, means for holding adetonator mounted beneath said firing chamber and adapted to be movedupwardly into the opening in said firing chamber, a valve assemblymounted on the upper end of said firing chamber, means for admitting anexplosive gas mixture having a predetermined flash temperature at apredetermined pressure to the interior of said chamber through saidvalve, and spark means mounted on said firing chamber and adapted uponactuation to ignite said explosive gas mixture thereby to fire anacceptable detonator disposed within said holding means.

5. A detonator testing apparatus comprising, means providing anexplosion chamber having an opening in the lower end thereof, a pair ofbrackets provided with elongated slots therein adapted to support saidexplosion chamber, means for holding a flash detonator mounted withinsaid slots and adapted to be moved vertically therein to a positionclosing the opening in the lower end of said explosion chamber, meanssupporting said detonator holding means within the opening, means foradmitting an explosive gas mixture of a predetermined pressure to theinterior of said chamber, and spark means mounted on said firing chamberand adapted upon actuation to ignite said explosive gas mixture therebyto fire an acceptable detonator disposed within said holding means.

6. In a device of the class described, means providing an explosivechamber having an opening in the lower end thereof, a pair of bracketshaving elongated slots therein supporting said explosion chamber, adetonator holder assembly slidably mounted in said slots and adapted tobe moved vertically in said slots to close the opening in said explosivechamber, a block pivotally mounted between said brackets, a leverfixedly mounted on said block, a pair of arms pivotally mounted on saidblock in oflset relation to the pivot point of said block with saidbrackets, the upper ends of said arms rotatably supporting saiddetonator holder assembly whereby upon movement of said lever the armsand said detonator holder are moved vertically in the slots in saidbrackets, means for admitting an explosive gas mixture having apredetermined flash temperature to the interior of said explosivechamber, and spark means mounted on said chamber for igniting saidexplosive gas mixture whereby upon movement of said lever to positionsaid detonator holder to close the opening in the explosive chamber andignition of said spark means an acceptable detonator will be fired bythe predetermined heat generated with combustion of said gas mixture.

7. A detonator tester comprising, a hollow cylinder, upper and lowerplates secured to said cylinder, saidlower plate having a central boretherein, brackets having slots therein supporting said cylinder, adetonator holder slidably mounted in said slots, said detonator holdercomprising three sleeves equidistantly spaced around the periphery ofsaid holder, a handwheel mounted on said holder and adapted to berotated to position one of said' sleeves vertically beneath the bore insaid lower plate, means for moving said detonator holder vertically insaid slots whereby said vertically positioned sleeve will be moved to aposition closing the opening in the lower plate, means for admitting anexplosive gas mixture having a predetermined flash temperature to saidcylinder, and means for providing a spark within said cylinder to ignitethe explosive gas mixture whereby upon actuation of said spark means toignite the gas mixture an acceptable test detonator held within thevertically positioned sleeve will be fired at said predeterminedtemperature.

8. A detonator testing apparatus comprising means providing an explosionchamber having an opening in the lower end thereof, a pair of bracketsprovided with elongated slots supporting said explosion chamber, adetonator holder rotatably and slidably mounted within said slots,sleeves equidistantly spaced around the periphery of said detonatorholder, a plurality of plungers respectively disposed in said sleeves,cam means slidably mounted within the slot in one of said brackets, saidcam means adapted to coact with said plungers whereby upon rotation ofsaid detonator holder one of the plungers is forced outwardly in thesleeve to eject a detonator held therein, means for moving saiddetonator holder vertically Within said slots whereby one of saidsleeves may be moved to a position closing the opening in the lower endof the explosion chamber, means for admitting an explosive gas mixturehaving a predetermined i'lash temperature to said chamber and means forproviding a spark within said chamber for igniting the explosive gasmixture therein whereby upon ignition of said explosive gas mixture anacceptable test detonator held by the sleeve within the opening in theexplosion chamber will be fired.

9. In a device of the class described, means providing an explosionchamber having an opening in the lower end thereof, brackets havingelongated slots therein supporting said explosion chamber, a detonatorholder slidably and rotatably mounted within said slots, a hand wheelmounted on said detonator holder, latching means mounted on one of saidbrackets and adapted to coact with said handwheel to prevent rotation ofsaid detonator holder in one direction, sleeves mounted on saiddetonator holder and spaced equidistantly around the periphery thereof,said sleeves having recesses in the outer ends thereof to receivedetonators, plungers' slidably disposed within said sleeves and springurged to a retracted position, cam means slidably mounted in the slot inone of said brackets, said cam means coacting with said plungers and soarranged as to urge one of said plungers outwardly in the sleeve thereofto eject a flash fired detonator held therein in response to rotation ofsaid handwheel through an angle corresponding to the angle ofdisplacement of said sleeves, means for moving said detonator holdervertically in the slots in said brackets so that one of said sleeves ispositioned to close the opening in, the lower end of said explosionchamber, means a for admitting an explosive gas mixture having a predetherein supporting said explosion chamber, a block having an offsetportion pivotally mounted between the lower ends of said brackets, alever fixed to said block, arms pivotally mounted on the offset portionof said block and extending upwardly therefrom, a detonator holderslidably mounted within the elongated slots in said brackets androtatably mounted on the upper ends of said arms whereby rotary movementof said lever imparts vertical movement to said detonator holder,sleeves mounted on said detonator holder spaced equidistantly around theperiphery thereof, a plurality of plungers slidably and respectivelydisposed within said sleeves and spring urged to a retracted position,cam means slidably mounted in the slot in one of said brackets andadapted to coact with said plungers, a handwheel secured to saiddetonator holder whereby upon rotation of said handwheel through anangle corresponding to the angular displacement of said sleeves one ofsaid plungers is forced outwardlyin the sleeve thereof to eject adetonator held therein, means for admitting an explosive gas mixturehaving a predetermined fiash temperature to said explosion chamber, andmeans for providing a spark within said explosion chamber whereby uponmovement of said lever said detonator holder and said sleeves are movedvertically and one of said sleeves having a detonator therein ispositioned within the opening in the explosion chamber and uponactuation of said spark means the explosive gas mixture is ignited tofire an acceptable test detonator when the firing temperature is thesame as or lower than theflash temperature of the gas mixture therebyproviding an indication of the firing temperature of said detonator;

ll. A flash-fired detonator testing apparatus comprising, meansproviding an explosive chamber having an opening in the bottom thereof,holding means for conraining a detonator to be tested, means adaptingthe holda ing means to be moved into engagement with the chamber at saidopening to close the opening therein, means for admitting a flammablegas and a combustion supporting gas as a combustible mixture ofproportions preselected to display a predetermined flash temperature ata prede: termined pressure in said chamber, said predetermined flashtemperature being commensurate with a required test temperature forfiring of an acceptable detonator, means for providing a spark Withinsaid explosion chamber after ,iosure thereof by said holding meanswhereby ignition of said spark means fires the mixture to subject thedetonate-r under test to said predetermined firing temperature conditionwithin said chamber thereby firing an acceptable detonator.

iteferences Cited in the file of this patent UNiTED STATES PATENTS DeIarlais Oct. 10, 1950

1. A FLASH FIRED DETONATOR TESTING APPARATUS COMPRISING, AN EXPLOSIONCHAMBER HAVING AN OPENING THEREIN, HOLDING MEANS FOR CONTAINING SAIDDETONATOR AND ADAPTED TO BE MOVED INTO ENGAGEMENT WITH SAID CHAMBER TOCLOSE THE OPENING THEREIN, MEANS FOR ADMITTING AN EXPLOSIVE GAS MIXTUREHAVING A PREDETERMINED FLASH TEMPERATURE TO THE INTERIOR OF SAID CHAMBERTO SUBJECT THE DETONATOR WITHIN SAID EXPLOSION CHAMBER TO SUBJECT THEDETONATOR UNDER TEST TO SAID PREDETERMINED FLASH TEMPERATURE OF SAIDEXPLOSIVE GAS MIXTURE THEREBY FIRING A SATISFACTROY DETONATOR.